Method for manufacture of processed foods from soybeans

ABSTRACT

Treating soybeans for use in processed foods, by submerging whole soybeans in water containing 0.1 to 0.5% of sulfurous acid and mother starter of lactic acid bacteria, crushing, skinning, and steaming said soybeans, and subjecting said soybeans to fermentation by inoculating a culture of microorganisms possessing proteolytic and soybean cotyledon cell macerating activity and then drying and pulverizing said soybeans.

United States Patent 91 Kanno et al.

[451 Feb. 27, 1973 METHOD FOR MANUFACTURE OF PROCESSED FOODS FROMSOYBEAN S [75 1 inventor? .lnweil lu i za semjlau i obi Kobayashi,Tokyo, both of Japan (73] AssigheJSiioW' snigya' "'Kiiii'h'ilii" 15515115,

Tokyo,Japan [22] Fried; mains 1'6" 211 App]. No.: 42,863

[52] U.S.Cl ..99/l7,99l99 [51] Int.Cl. ..A23I1/20 [58] FieIdofSearch..99l98,99,l7,64

[56] References Cited UNITED STATES PATENTS 2,052,215 8/1936 Cohn..99/99 3,585,047 6/1971 Fujimakietal "99/99 FOREIGN PATENTS ORAPPLICATIONS 478,570 1/1938 Great Britain ..99/17 Primary Examiner-A.Louis Monacell Assistant Examiner-J. M. Hunter Attorney-Holman and Stern5 7 ABSTRACT Treating soybeans for use in processed foods, by submergingwhole soybeans in water containing 01 to 0.5% of sulfurous acid andmother starter of lactic acid bacteria, crushing, skinning, and steamingsaid soybeans, and subjecting said soybeans to fermentation byinoculating a culture of microorganisms possessing proteolytic andsoybean cotyledon cell macerating activity and then drying andpuIverizing said soybeans.

6 Claims, No Drawings METHOD FOR MANUFACTURE OF PROCESSED FOODS FROMSOYBEANS This invention relates to processed foods, and moreparticularly to a method of making processed foods from soybeans.

The primary object of the present invention is to manufacture processedfoods from soybeans without bitter taste and off flavor.

Another object of the present invention is to provide a raw material,which can be used in numerous processed foods from soybeanseconomically.

Soybean milk is a drink made from soybeans and, because of its low costof production, good digestibility and high nutrition, it is widely usedin such areas as Hong Kong, Formosa, and Southeast Asia. But in Japan,countries of Europeand the United States of v America, the use ofsoybean milk is limited to special purposes such as a milk substitutefor milk allergic infants, religious vegetarians, and patients underdietary treatments.

There have been attempts to produce numerous foods from defattedsoybeans, but successful applications can only be found in themanufacture of soybean paste (miso), soybean sauce, tofu (soybean curd),and are remarkably rare compared with milk products. The first reasonfor this is the bitter taste and off of soybeans and soybean products.

Another reason which may be cited is that economical mass production hasnot been possible for soybean milk.

Therefore, to promote industries for the manufacture of processed foodsfrom soybeans, it is necessary not only to remove the bitter taste andoff flavor of soybeans but to develop an economical method of treatmentsuitable for mass production of the material.

The process of the present invention is illustrated as follows;

Soybeans Selection (removing of foreign materials) immersion in waterSulfurous acid vapor oculation of Lactic acid bacteria Immersion insulfuric acid solution Lactic acid fermentation Removal of waterCrushing Heating by steaming Grinding Inoculation of microorganismsFermentation (Water content about 60., percent) neutralization Dryingunder vacuum condition Pulverization Product.

As shown in the foregoing flow description, one of the maincharacteristics of the present invention is that immersion of soybeansin sulfurous acid solution and lactic acid fermentation are carried outsimultaneously, such a process hitherto has never been practiced.

By carrying out the above treatment the removal of the taste and offflavor components of raw soybeans can effectively be accomplished. Theseeffects are increased by the fermentation step, followed by inoculationof microorganisms. The product thus obtained has excellent flavor and isentirely free of bitter taste and off flavor.

By blowing sulfurous acid gas into the water in which soybeans areimmersed, the pH value of the water comes to nearly the isoelectricpoint of soybean protein, and reduction of the yield of the product bythe soybean protein into the water can be avoided.

The fennentation by inoculation of microorganisms can be carried out inthe pasty medium, water content of which is about percent. The drying ofthe product can then be carried out more economically compared withusual soybean milk (water content of which is about 90 percent)production.

The characteristics of the present invention are as follows:

1. Immersion of soybeans in sulfurous acid solution This step may beperformed under substantially the same conditions as the wet process ofcorn starch production. But in the corn starch production, immersion inthe sulfurous acid solution is intended primarily for the separation ofstarch making up about percent in corn grain. Whereas, the object of theprocess of the present invention is entirely different from the processof the corn starch production. (The starch content of soybean is lessthan 0.1 percent contained in the cotyledon).

The object of immersing the soybeans in sulfurous acid solution is tosoften and to collapse the bonds of the protein body and spherosomegranule in the colyledon cells of the soybeans and to remove thesubstances contained in them, such as weak acids, soluble sugars,non-proteinous nitrogen compounds, off flavor substances and most of thewater soluble physiological inhibitors.

By inoculating the mother starter of sulfurous acid resistivelactic-acid bacteria (for example, Lactobacillus delbruckii) in theimmersion solution, lactic-acid is produced in the immersion solution.The cotyledon cells, which absorb moisture and swell, are subjected tosoftening and collapsing action of the sulfurous acid, and lactic acid.

2. Heating by steam The object of this step is to increase the effect ofthe above step (I), and to inactivate the physiological inhibitors suchas urease and trypsin inhibitor, and enzymes such as lipoxidase.

Lipoxidase acts on lipid in soybeans during its pulverization and formsa large amount of peroxide which is considered to be a source of offflavor in the soybeans.

In the method of the present invention, soybeans are pulverized afterthe inactivation of lipoxidase, thereby avoiding the formation of offflavor.

3. Fermentation I This step is characterized by inoculating a culture ofmicroorganisms, having the remarkable proteolytic activities andmacerating activities of cotyledon cells, to the medium containingsoybeans treated by the steps shown in (l) and (2).

Microorganisms having the foregoing activities are Neurospora sitophila,Aspergillus niger, Rhizopus niveus, and Bacillus subtilis, which arecommonly available.

The macerating activities of microorganisms can be tested by thefollowing method;

Soaking skinned soybeans in water, steaming said skinned soybeans for 30minutes, crushing said steamed soybeans coarsely, inoculating saidsoybeans with 10 times (in weight) of a culture of microorganisms,shaking for one hour under 30C, and observing whether saidmicroorganisms have macerated said soybeans until the original form ofsaid soybeans disappears completely or not.

In the method of the present invention, the protein of soybeans isslightly macerated by soaking soybeans in sulfurous acid solution, inwhich lactic acid bacteria were inoculated, and then by incubatingmicroorganisms which retain protease of high activity and highmacerating activity, the components of soybeans are subjected tocomplicated enzymatic decomposition. Off flavor material contained incotyledon cells can completely be decomposed and owing to polypeptideswhich are formed by the slight decomposition of high molecular protein,a fair seasoning effect can be expected.

By the process of the present invention, a product of good flavor, whichentirely differs from usual soybean milk and processed soybean products,can be obtained.

Example 1 I parts of selected soybeans are washed with water, and aresoaked for 24 hours at 55C in water to which 0.5 percent of sulfurousacid and mother starter of lactic acid bacteria (for exampleLactobacillus delbrukii) have been added.

After dehydration, the soybeans are coarsely crushed, washed with water,skinned, and steamed at 100C for minutes. Soybeans thus treated areground into paste by a chopper.

To this paste thus obtained, 5 parts of culture of Neurospora Sitophilaare inoculated, and the mixture is fermented for 4 hours at 30C. Afterthis fermentation, the fermented material is neutralized, dried under avacuum of mm Hg. at 40C, pulverized, and 80 parts of powdered soybeanmilk product (moisture content 8 percent) of less than 40 mesh isobtained.

This product retains a mild and delicious flavor, without bitter tasteand off flavor.

Example 2 The fermentation is carried out as described in Exampleinoculating with Bacillus subtiiis instead of Neurospora sitophila,piling inoculated material, and incubating at 45C for 3 hours.

The fermented material is pulverized and 80 parts of the pulverizedproduct for soybean milk (moisture content 8 percent) is obtained.

Using the products obtained by the process described in Examples 1 and2, and three commercial powdered soybean milk products, samples ofsoybean milk are prepared according to the following prescriptions. Theorganoleptic tests by a panel of 30 members in accordance with theKramers Sensory Test are carried out with the samples of soybean milk at20C.

By these tests, it was found that the products according to Examples 1and 2 were more favored than the commercial products, with a 5% level ofsignificance.

Prescription Pulverized soybean products 400 g Salt 0.5 g Sugar 10 gWater 600 ml Boiling 2 minutes The product of the present invention issuitable not only for materials for soybean milk but also for materialsfor various pasty foods, noodles, breads and cakes,

What we claim: l. A method for the manufacture of a material ofprocessed foods from soybeans, comprising the steps of submerging wholesoybeans in water containing 0.1 to 0.5 percent of sulfurous acid andmother starter of lactic acid bacteria, crushing, skinning, and steamingsaid soybeans, subjecting said soybeans to fermentation by inoculating aculture of microorganisms possessing proteolytic and soybean cotyledoncells macerating activity, said microorganisms being selected from thegroup consisting of Neurospora sitophila, Aspergillus niger, Rhizopusniveus, and Bacillus subtilis, and then drying and pulverizing saidsoybeans.

2. A method for the manufacture of a material of processed foods asclaimed in claim 1, wherein lactic acid bacteria inoculated as a motherstarter is Lactobacillus delbrukii.

3. A method for the manufacture of a material or processed foods asclaimed in claim 1, further comprising pasting the soybeans prior tofermentation.

4. A method for the manufacture of a material of processed foods asclaimed in claim 1, further comprising coarsely crushing the soybeansprior to fermentation.

5. A method for the manufacture of a material of processed foods asclaimed in claim 1, wherein the submerging step of the whole soybeans inwater is carried out for 24 hours at 55C.

6. A method for the manufacture of a material of processed foods, asclaimed in claim 1, wherein the fermentation step by inoculating aculture of microorganisms is carried out for 3 or 4 hours at 45 or 30Crespectively.

2. A method for the manufacture of a material of processed foods asclaimed in claim 1, wherein lactic acid bacteria inoculated as a motherstarter is Lactobacillus delbrukii.
 3. A method for the manufacture of amaterial or processed foods as claimed in claim 1, further comprisingpasting the soybeans prior to fermentation.
 4. A method for themanufacture of a material of processed foods as claimed in claim 1,further comprising coarsely crushing the soybeans prior to fermentation.5. A method for the manufacture of a material of processed foods asclaimed in claim 1, wherein the submerging step of the whole soybeans inwater is carried out for 24 hours at 55*C.
 6. A method for themanufacture of a material of processed foods, as claimed in claim 1,wherein the fermentation step by inoculating a culture of microorganismsis carried out for 3 or 4 hours at 45* or 30*C respectively.